This invention relates to support platforms, particularly but not exclusively to bridges and methods of construction thereof.
Bridges for roads and walkways have traditionally been constructed from heavy materials such as stone, steel or reinforced concrete. Conventional bridges comprise a contact surface over which a load, for example road vehicles, may pass. The contact surface must meet design criteria including wear performance, longevity, slip resistance and the ability to drain water from the contact surface. The contact surface of a bridge is not usually capable of carrying its own weight and requires to be supported by a decking. The decking provides structural support to the contact surface and transfers the load to the main bridge structure. Secondary features such as footpaths, barriers or railings can be considered as part of the decking. The main bridge structure or superstructure carries all of the elements of a bridge across the distance that the bridge must span. The design of the superstructure is complex and must take account of criteria such as seismic design, expansion considerations, substructure design and wind loadings.
The transient load of the majority of modern bridge designs will typically be in the form of vehicular traffic and the details are specified in recognised standards. An example is; AASHTO LRFD Bridge Design Specifications, Customary U.S. Units, 4th Edition with 2008 and 2009 U.S. Edition Interims. Standard-Item Code: 15-LRFDUS-4-M. Applying these standards to bridge design allows one to determine the transient loads that must be applied to a bridge design. The transient load offers no opportunity for weight reduction as it is fixed by national and international standards and the bridge must be designed to carry the required loadings.
It is an object of the present invention to provide a decking and contact surface system for construction of bridges or other support platforms, for example for railway passenger platforms. The support platforms in accordance with this invention are referred to in this specification for simplicity as “bridges”.
It is a further object to provide a deck system for road bridges. It is another object to provide a decking and contact surface for a bridge. It is a further object to provide a method of construction of a bridge, especially a road bridge.